From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Bonnet and scuttle ventilation, engine protection from dirt, and dashboard insulation.
| Identifier | ExFiles\Box 19\4\ Scan017 | |
| Date | 5th June 1930 guessed | |
| [Handwritten in blue ink at top] we cannot get away with-2 this for high speed touring in hot weather [Handwritten in blue ink on left] we think that front shutters may be more important than back shutters [Handwritten in red ink on left] This wants investigating again [Handwritten in blue ink at bottom left] we think the side ventilation of scuttle useless in any case! The easiest way to keep the driving seats cool is without ventilating the bonnet along the scuttle is to ventilate [Typed text] Mr. Ainsworth is therefore suggesting that we should have an absolutely plain bonnet on L.H. P.II. What do you think of this suggestion? (3) "Cannot more air be taken away through the side plates and underneath the dash?" This raises a question which we took up with you several years ago on the S. Ghost. At that time we found that all mud came from the contact of front tires with the ground and moved relative to the car at an angle of not more than 30º with the longitudinal axis. Consequently if the bottom of the flywheel was protected and one or two control points like the bottom end of the pendulum lever and steering column starting motor chain etc., the undershields could be removed entirely without any undue accumulation of dirt on the engine. Now that the flywheel is enclosed it would appear that there is little need for any undershields. I wonder whether we have verified this, and whether there is any benefit in engine house temperature? I recall that what we did find on the S. Ghost as the chief cause of dirty engines, was running on dirt roads in dry weather. In Georgia in summer for example, the engine is caked with red clay after a few hours. Undershields are no protection as this dirt comes through the radiator. (4) B.W.A. confirms that if any ventilation is fitted we should prefer shutters to louvres, but that from our experience to date, bonnet ventilation is unnecessary as we do not get much trouble from overheating over the whole U.S. Also, that we prefer the plain bonnet by reason of the problem of scuttle-ventilation. Finally, on my suggestion for an insulated dashboard with "false dash" and air space between, he amplifies this as follows:- "The quietest car from an engine standpoint which I have ever driven is the gray 318-FM with Warwick body, on which I had an insulated dash with an air space. This engine was cont'd.{John DeLooze - Company Secretary} | ||